1. Field of the Invention
The present invention relates to an electronic device and control method for the electronic device, and particularly relates to an electronic device wherein the operating modes of the electronic device can be switched between a drive mode and a power saving mode, and a control method for the electronic device.
2. Description of the Related Art
An example of an electronic device of recent years is the electronic wristwatch. These wristwatches contain a power supply, the power supply including a power generating device having a rotating weight, and a storage unit (e.g. high-capacity capacitor) for storing electrical energy generated by the power generating device. This type of electronic timepiece is capable of operating as a watch for long periods of time without battery replacement because the time display is performed by supplying electrical energy delivered from the capacitor to the time display unit.
In this way, electronic timepieces having power generating devices supply stable electrical energy for long periods of time. Thus, when the power generating device has been in a non-generating state for a predetermined period of time or when the electronic timepiece is removed from the user""s wrist, for example, the condition is detected, and the operating mode of the electronic timepiece is switched from an active mode (display mode) in which time display is performed to a power saving mode in which time display is not performed.
Here, in the power saving mode of the electronic timepiece, time display is not performed, and electrical energy is supplied only to a control circuit for keeping track of the current time. On the other hand, in the display mode (active mode) in which the normal time display is performed, not only is electrical energy supplied to the control circuit, but for example in the case of an analog watch, electrical energy is also supplied to the drive circuit for moving the hands.
When a user puts an electronic timepiece that is in power-saving mode onto his wrist and power generation commences, a switch is made from the power-saving mode to the display mode, and in the time display unit, the display is restored to the current time based on the data stored in a counter. For example, in an analog watch using hands, the hands are sped forward to restore it to the current time.
However, when an electronic timepiece continues to be in the power-saving (non-generating period) for a long time, the electrical energy stored in the high-capacity capacitor is gradually consumed. For this reason, when there is very little electrical energy in the high-capacity capacitor, restoration to the current time becomes impossible. Additionally, in this case, a lot of time is required to accumulate enough electrical energy to reactivate the time display unit itself, so that there is a risk to the re-activating ability of the electronic timepiece.
The present invention has been made in consideration of the above-described situation, and offers an electronic device and control method for the electronic device wherein, when there is not enough electrical energy to return to the current time in the power supply during the power-saving mode, the consumption of electrical energy is reduced to preserve the electrical energy of the power supply, thus enabling the driven unit to be quickly reactivated.
A first embodiment of the present invention is characterized by comprising a chargeable power supply unit for supplying electrical energy, a drive control unit operated by the electrical energy supplied from said power supply unit, for outputting a drive signal; a driven unit driven by said drive signal, a mode switching unit for switching the operating mode of said driven unit between a drive mode for normal operation and a power-saving mode based on a preset first condition; and an operation suspending unit for suspending operation of said drive control unit when the amount of electrical energy stored in said power supply unit is determined to be smaller than a predetermined electrical energy amount based on a preset second condition while in a power-saving mode due to said mode switching unit.
A second embodiment of the present invention is characterized by that in the first embodiment of the present invention said operation suspending unit suspends supply of the electrical energy from said power supply unit to said drive control unit when suspending the operation of said drive control unit.
A third embodiment of the present invention is characterized by that in the first embodiment of the present invention said drive control unit comprises a control circuit operated by electrical energy supplied from said power supply unit, for outputting a control signal, and a drive circuit operated by electrical energy supplied from said power supply unit, for outputting a drive signal to said driven unit based on the control signal, and said mode switching unit supplies electrical energy to said control circuit and drive circuit in said drive mode, and supplies electrical energy to only said control circuit in power-saving mode.
A fourth embodiment of the present invention is characterized by that in the first embodiment of the present invention said power supply unit comprises a power generating unit for converting external energy into electrical energy, and a power storing unit for storing electrical energy supplied from said power generating unit and supplying the electrical energy to said drive control unit.
A fifth embodiment of the present invention is characterized by that in the first embodiment of the present invention said power storing unit comprises an auxiliary battery or a capacitor.
A sixth embodiment of the present invention is characterized by that in the fourth embodiment of the present invention a power generation state detecting unit for detecting whether or not said power generating unit is in a power generation state is provided, and said first condition is whether or not said power generating unit is in a power generating state is determined by said power generation state detecting unit.
A seventh embodiment of the present invention is characterized by that in the sixth embodiment of the present invention said power generation state detecting unit comprises an energy amount determining unit for determining whether or not the amount of electrical energy output from said power generating unit exceeds a criterion energy amount, and a power generation time determining unit for determining whether or not a duration over which the electrical energy amount is determined by said energy amount determining unit as to exceed the criterion energy amount exceeds a criterion time value.
An eighth embodiment of the present invention is characterized by that in the first embodiment of the present invention a carriage state detecting unit for detecting whether or not said electronic device is in a carried state is provided, and said first condition requires, for switching the operating mode of said driven unit from said drive mode to said power-saving mode, that when said electronic device is found to be in a non-carried state by said carriage state detecting unit, and the duration over which the electronic device is in a non-carried state continues for a predetermined time, and said first condition requires, for switching the operating mode of said driven unit from said power-saving mode to said drive mode, that when the electronic device has switched from a non-carried state to a carried state according to said carriage state detecting unit.
A ninth embodiment of the present invention is characterized by that in the first embodiment of the present invention a voltage detecting unit for detecting the voltage of said power supply unit is provided, and said second condition requires that the voltage of said power supply unit detected by said voltage detecting unit goes below a predetermined voltage.
A tenth embodiment of the present invention is characterized by that in the first embodiment of the present invention an electrical energy detecting unit for detecting the amount of electrical energy supplied from said power supply unit is provided, and said second condition requires that the amount of electrical energy capable of being supplied by said power supply unit detected by said electrical energy amount detecting unit becomes smaller than a predetermined amount of electrical energy required to restore the operating mode of said drive unit from said power-saving mode to said drive mode.
An eleventh embodiment of the present invention is characterized by that in the fourth embodiment of the present invention a power generation state detecting unit for detecting whether or not said power generating unit is in a power generating state is provided, an operation initiating unit for initiating operation of said drive control unit when a preset third condition is fulfilled while the operation of said drive control unit is in a suspended state due to said operation suspending unit is provided, and said third condition requires that initiation of power generation by said power generating unit is detected by said power generation state detecting unit.
A twelfth embodiment of the present invention is characterized by that in the eleventh embodiment of the present invention the initiation of power generation of said third condition means that when the amount of electrical energy output from said power generating unit exceeds an energy amount sufficient for reactivation, and this state continues for a predetermined duration.
A thirteenth embodiment of the present invention is characterized by that in the first embodiment of the present invention a carriage state detecting unit for detecting whether or not said electronic device is in a carried state is provided, an operation initiating unit for initiating operation of said drive control unit based on a preset third condition when the operation of said drive control unit is in a suspended state due to said operation suspending unit is provided, and said operation initiating unit determines when said electronic device is switched from a non-carried state to a carried state by said carriage state detecting unit as said third condition.
A fourteenth embodiment of the present invention is characterized by that in the thirteenth embodiment of the present invention the switch from said non-carried state to the carried state is made when the carried state continues for a predetermined duration after switching from a non-carried state to a carried state.
A fifteenth embodiment of the present invention is characterized by that in the first embodiment of the present invention an external operation input unit for a user to perform operations from the outside is provided, and the switch from said drive mode to said power-saving mode is performed by said mode switching unit based on the operating conditions of said external operation input unit.
A sixteenth embodiment of the present invention is characterized by that in the first embodiment of the present invention an external operation input unit for a user to perform operations from the outside is provided, and an operation initiating unit for initiating operation of said drive control unit based on operating conditions of said external operation input unit when said operation suspending unit detects that the operations of said drive control unit are in a suspended state is provided.
A seventeenth embodiment of the present invention is characterized by that in any one of the first to sixteenth embodiments of the present invention said driven unit has a time display unit for displaying the time.
An eighteenth embodiment of the present invention is characterized by that in the seventeenth embodiment of the present invention said drive control unit comprises a current time restoring unit for restoring the time display to the current time when the operating mode of the driven unit is switched from said power-saving mode to said drive mode by the mode switching unit.
A nineteenth embodiment of the present invention is characterized by that in the eighteenth embodiment of the present invention an electronic device said predetermined electrical energy amount is set to an electrical energy amount required to restore the current time from the power-saving mode using said current time restoring unit.
A twentieth embodiment of the present invention is characterized by that in the eighteenth embodiment of the present invention the amount of energy sufficient to perform restoration is set to a minimum amount required to enable time display using said time display unit by initiating the operation of said drive control unit.
A twenty-first embodiment of the present invention is characterized by that in the eighteenth embodiment of the present invention said time display unit has hands for displaying the time and a motor for driving said hands, and said current time restoring unit restores the motion of the hands by said motor by restoring them at a high-speed hand-moving speed which is higher than the normal hand-moving speed.
A twenty-second embodiment of the present invention is characterized by that in the first embodiment of the present invention said drive control unit comprises a control circuit operated by electrical energy supplied from said power supply unit, for outputting a control signal, and a drive circuit operated by electrical energy supplied from said power supply unit, for receiving the control signal and outputting a drive signal to said driven unit, said control circuit comprises an oscillator circuit for generating a reference pulse, and said operation suspending unit suspends the operation of said oscillator circuit.
A twenty-third embodiment of the present invention is characterized by that in the twenty-second embodiment of the present invention said operation suspending unit suspends the supply of electrical energy to said oscillator circuit.
A twenty-fourth embodiment of the present invention is characterized by that in the first embodiment of the present invention said drive control unit comprises a control circuit operated by electrical energy supplied from said power supply unit, for outputting a control signal, and a drive circuit operated by electrical energy supplied from said power supply unit, for receiving the control signal and outputting a drive signal to said driven unit, said control circuit comprises an oscillator circuit for generating a reference pulse, and a divider circuit for dividing the reference pulse output from said oscillator circuit, and said operation suspending unit suspends operation of said oscillator circuit or said divider circuit.
A twenty-fifth embodiment of the present invention is characterized by that in the twenty-fourth embodiment of the present invention said operation suspending unit comprises a regulated voltage generating circuit for generating a constant voltage lower than the power supply voltage for driving at least one of the oscillator circuit and the divider circuit, and suspends the supply of electrical energy to said regulated voltage generating circuit.
A twenty-sixth embodiment of the present invention is characterized by a control method for an electronic device comprising a chargeable power supply unit for supplying electrical energy, a drive control unit operated by the electrical energy supplied by said power supply unit, for outputting a drive signal, and a driven unit driven by receiving the drive signal output from said drive control unit, the control method comprising a mode switching step of switching an operating mode of said driven unit between a drive mode and a power-saving mode based on a preset first condition, and a drive suspending step of suspending operation of said drive control unit when the amount of electrical energy stored in said power supply unit is determined to be smaller than a predetermined amount of electrical energy according to a preset second condition, while the operation mode is set to the power-saving mode by said mode switching step.
A twenty-seventh embodiment of the present invention is characterized by that in the twenty-sixth embodiment of the present invention said power supply unit comprises a power generating device for converting external energy into electrical energy, and a power storing device for storing electrical energy supplied from said power generating device and supplying said electrical energy to said drive control unit, the method further comprising a generation state detecting step of determining whether or not power is being generated by said power generating device, and wherein said first condition is whether or not power is being generated by said power generating device according to said power generation state detecting step.
A twenty-eighth embodiment of the present invention is characterized by that in the twenty-seventh embodiment of the present invention said power generation state detecting step comprises an energy amount determining step for determining whether or not the amount of electrical energy output from said power generating device has exceeded a criterion energy amount, and a power generation time determining step of determining whether or not the duration over which the electrical energy amount exceeding the criterion energy amount is determined in said energy amount determining step exceeds a criterion time value.
A twenty-ninth embodiment of the present invention is characterized by that in the twenty-sixth embodiment of the present invention said electronic device has a carriage state detecting step for detecting whether or not it is being carried, said first condition requires, for switching the operating mode of said driven unit from said drive mode to said power-saving mode, that said electronic device is detected to be in a non-carried state in said carriage state detecting step, and the time over which said electronic device is in a non-carried state continues for a predetermined time, and said first condition requires, for switching the operating mode of said drive unit from said power-saving mode to said drive mode, that a switch from the non-carried state to a carried state is detected in said carriage state detecting step.
A thirtieth embodiment of the present invention is characterized by further comprising, in the twenty-sixth embodiment of the present invention, an electrical energy amount detecting step for detecting an amount of electrical energy supplied from said power supply unit, and said second condition is when the electrical energy amount capable of being supplied by said power supply unit detected by said electrical energy detecting step is smaller than a predetermined electrical energy amount required to restore the operating mode of said driven unit from said power-saving mode to said drive mode.
A thirty-first embodiment of the present invention is characterized by that in the twenty-sixth embodiment of the present invention said power supply unit comprises a power generating device for converting external energy into electrical energy, and a power storing device for storing electrical energy supplied from said power generating device, and supplying said electrical energy to said drive control unit, the method comprises a power generation state detecting step of detecting whether or not said power generating device is in a power generation state, and further comprises an operation initiating step of initiating operation of the drive control unit based on a preset third condition when the operation of said drive control unit being in a suspended state is determined in said operation suspending step, and said third condition requires that said power generating device initiating power generation is detected in said power generation state detecting step.
A thirty-second embodiment of the present invention is characterized by that in the twenty-sixth embodiment of the present invention said power supply unit comprises a power generating device for converting external energy into electrical energy, and a power storing device for storing electrical energy supplied from said power generating device, and supplying said electrical energy to said drive control unit, said method comprises a carriage state detecting step for detecting whether or not said electronic device is in a carried state, and further comprises an operation initiating step of initiating operation of the drive control unit based on a preset third condition when the operation of said drive control unit is in a suspended state due to said operation suspending step, said third condition requires that when said electronic device is detected as having switched from a non-carried state to a carried state in said carriage state detecting step.